Waterproof paper and method of producing the same



Aug. 10 1926.

W. M. WHEILDON Filed June 16. 1921 Patented Aug. 10,

ON, OF FBAMINGHAM, MASSACHUSETTS, ASSIGNOR OF FRAMINGHAM,

WILLIAM E. WHEILD WATERPBOO This invention relates to waterproofpawANGIER,

Application filed June 16, 1921. Serial No. 478,138.

pers and to a method of producing the same. provide strength adaptableThe more particular purpose is to a waterproof for wrapping purposespaper of substantial and yet one-which may be of relatively lightweight.

applicable for producing in waterproof which are converted, that is, tothe action of some mechanism or papers jected The invention is alsoparticularly form subprocess to change their properties from those ofordinary finished paper.

invention will best be understood by reference to the followingdescription taken in drawings,

Fig. 1 is a a method of and connection with the accompanying whereindiagrammatic view illustrating producing waterproof paper Fig. 2 is asimilar view illustrating the production of waterproof craped paper.

The nature of the improved waterproof paper which forms the subject ofmy invention may be conveniently understood by a description of a methodof making the same.

Referring, therefore, to

Fig. 1, I there show at 3 a roll of paper which is preferably of thekind known as havinga body contrasted with loose material. One facekraft or similar paper of substantial strength as felt-like and bibulousof the web 3 may be coated with a suitable waterproofing material havingadhesive properties to use what is known as.

purpose I prefer and for this black asphalt, a bituminous product whichis the pitchy residue of oil distillation. A

second web of paper 7 is roll and superposed of the web 3 and the tworolls 9, thus providing a duplex of squeeze led from its supply on thecoated face are united by means web consisting of sheets of paper withan intervening layer of asphalt, the whole presenting at the outsideclean surfaces of paper and forming an easily handled unit. The duplexweb is then subjected to heat as indicated diagrammatically in Fig. 1 bythe drier chamber 11 containing steam pipes 13 to such extent as to meltthe fusible asphalt and to absorb it into the-body of the sheets 3 and7.

until the asphalt coating is entirely absorbed and then readily separatetwo This process 1s carried on substantially the two sheets 3 and 7 andmay be wound up S PATENT OFFICE.

, T0 EDWARD MASSACHUSETTS.

F PAPER ANDLMETHOD OF PRODUCING THE SAME.

separately as indicated at the right of the figure.

The resulting product is a paper which, while it may be relatively thin,is of a strong, resistant character like rdinary krai't paper and whichis saturated with pitch. That is, the pitch is absorbed completely intothe body an impervious layer. By saturation I do not mean that themaximum possible amount of pitch is applied to the paper. In fact thebest results are obtained from the use of a lesser amount ofwaterproofing material giving the paper adequate water-resistingproperties while leaving it non-tacky and in a condition wherein it maybe readily handled. Theprocess described makes it possible topredetermine the amount of waterproofing material applied to the paper.The coating originally applied to the sheet 3 is drawn in to the body ofthe paper in such a way that the improved waterproof paper presents anon-tacking surface. That is, the asphalt is not on the outside of thepaper in such a manner that it may stick to or smear adj acent articleson which the paper is used.

My invention is particularly applicable to the production of paperswhich are in some way processed and, in particular, where this processentails a wetting of the original finished paper the results areparticularly advantageous. Thus in Fig. 2 of the drawing I there showdiagrammatically the production of waterproof craped paper of a naturesimilar to that described in Fig. 1 but also provided with crapes torender the same expansible and elastic. The two webs of paper 3 and 7 asbefore are united by an intervening layer of asphalt. The completed'duplex web may then be passed through the saturating bath 15 of acraping machine of ordinary type, caused to adhere to the craping roll17 and while adherent thereto crowded back on itself by the doctor blade19, the moist Web being craped by the action of the doctor in well knownmanner. The moist craped web then passes to the drying chamber 11. Theweb is dried and the crinkling made permanent but the heating iscontinued as before in such manner that the asphalt is absorbedcompletely by the paper so that the webs 3 and 7 may be separated,Cilk'll as a single crapcd thickness of paper efficiently waterproofed.

- it offers no resistance to the softening of these outside webs by thesaturating, bath 15 inorder to make the paper fit for craping.Thereafter the necessary drying step for drying the craped paper iscombined with the heating which causes absorption of the asphalt withresultant economy. The soaking of the paper for craping purposes alsoopens the pores thereof and renders it more penetrable' by thewaterproofing pitch which is later absorbed into the same.

are treated with the same.

The material produced by the process illustrated in Fig. 2 is a singlethickness of strong paper, Waterproof but having a nontacking surfacewhich is irregularly craped. The rough surface of ordinary craped papercauses difficulties if it is attempted to Waterproof the material aftercraping. In

' the present instance the asphalt is uniformly applied to the uncrapedsheet and all parts On the other hand, if a single sheet of uncrapedmaterial were effectively waterproofed, it would resist the softeningaction of the bath 15 of the craping machine or this bath wouldadversely affect the waterproofing material and perhaps cause it to runand smear and gum the 1 machine parts. In the present instance this doesnot take place and the two webs 3 and 7' absorb the waterproofingmaterial after they have been craped, which waterproofing material'hasbeen applied before the craping operation in such a manner that it doesnot adversely affect that operation.

- way of example in the accompanying draw- "ing, what I claim as new anddesire to se- Having thus described in detail theparticular'embodiment'of my invention shown by cure by Letters Patent Ishall express in the following claims. Claims 1. A waterproof paperconsisting of a crinkled base impregnated with pitch and having anon-tacking surface. v

2. The method of preparing craped waterproof paper comprising connectingtwo layers with fusible adhesive waterproofing material, wetting theduplex layer and craping the same and then heating it to absorb thematerial in the layers and separating them.

3. The method of preparing in waterproof form sheet material which isfinished by a process involving wetting the same characterized byjoining two layers of unprocessed sheet material by fusible adhesivewaterproofing material, processing the assembly and then heating them toabsorb the waterproofing material into the layers and separating them.

4. The method of preparing in waterproof form paper which is convertedby the action of mechanism thereon characterized by joining two layersof unprocessed mate rial by waterproofing adhesive to rovide a duplexunit which may be handled by such mechanism without smearing or gummingof the same, processing the duplex unit, and therafter absorbing suchadhesive into the layers and separating the same.

5; The method of preparing paper having bituminous waterproofingmaterial absorbed into the body thereof comprisin assembling two sheetswith said WVEIIBIPIOO material interposed and heating the assem ly toabsorb the material into the sheets.

6. The method of preparing paper having bituminous waterproofingmaterial absorbed into the body thereof comprising superficially coatinga sheet with such material, applying a second sheet thereof and heatingthe assembly to absorb the material into the sheets;

In testimony whereof, I have signed my name to this specification.

WILLIAM M. WHEILDON.

